The value of clustering to provide inexpensive computing is widely known for web serving, high performance computing and other fields. However, the size of the clusters has generally stagnated at around 512 nodes, due largely in part to the problem of how to initially set up larger clusters with a version of the operating system. Clusters today typically employ either the single server technique or the hierarchical servers technique to install a cluster.
In the single server technique, all nodes are installed from a single workstation that has all the intelligence and software to be an installation server (i.e. extra software required for installation in addition to the operating system software common to the ordinary CPUs (nodes in the system). In the hierarchical technique, the primary server installs a secondary set of installation servers and propagation of the operating system occurs in tightly controlled “waves”. The primary server installs the secondary servers, which install the remainder of the clients. Both methods suffer from a phenomenon known as “broadcast storms”. Broadcast storms occur when many nodes are powered up and broadcast network packets at regular short intervals simultaneously, saturating the network and eventually causing all network traffic to fail.